Devices known as ‘lab on a disc’ devices allow the mixing, sequencing, and control of volumes of liquids. The liquid may be caused to flow through such a device under the action of centrifugal force, by rotating the device about an axis of rotation. Alternatively, liquid flow in the device may be induced by other means, for example pressure-driven flow and capillary driven flow.
Processing of liquid on a ‘lab on a disc’ device may require the mixing of a liquid, for example a liquid comprising two or more components, or the resuspending of one or more dry reagents in a liquid. In the case of microfluidic devices in particular, achieving effective mixing of two liquids, or a liquid and a dry reagent, can be a challenge, particularly when dealing with the small volumes of liquid that are typically used with microfluidic devices. It would therefore be useful to have structure which facilitates the effective mixing of a liquid on such a device.